1. Field of the invention
This invention relates to a kingpin assembly and more particularly to a shimless adjustable kingpin assembly for motor vehicles and the like.
2. Description of the Prior Art
In one conventional front suspension for a vehicle such as a truck, the front axle is connected to wheel supporting spindle or trucks by a kingpin. Commonly, the spindle assembly has a yoke portion and the end of the axle has an aperture. The kingpin extends through aligned holes in the yoke portion and the aperture in the axle to provide a means for the spindle to pivot about a vertical steering axis.
Kingpin assemblies conventionally have been made with a kingpin having each end rotatably mounted in the holes in upper and lower arms which form the yoke of the spindle. The aperture end of the axle forms a knuckle support that is located between the upper and lower arms of the yoke of the spindle or knuckle. The knuckle support is either rotatably or non rotatably engaged to the kingpin. Bearings are usually mounted between the knuckle support at the end of the axle and lower arm of the spindle yoke to permit the low frictional movement of the spindle about a vertical steering axis with respect to the axle.
Due to manufacturing tolerances, the knuckle support and kingpin bearing are often not precisely fitted between the upper and lower arms of the yoke. A gap or clearance created allows the knuckle to longitudinally move along the kingpin and move away from the bearings. Jolts and bumps can cause the jostling of the knuckle or spindles to rapidly move up and down which can produce extreme and often harmful stresses on the bearing. The extreme and harmful stresses can shorten the useful life of the bearings.
Conventionally, the way to eliminate the problem of excessive vertical play (i.e. vertical movement of the knuckle support relative to the kingpin bearing) is to put one or more shims between the upper arm of the spindle and knuckle. The shims fill in the gap such that the end of the axle, the bearing and shims snugly fit between the lower and upper arms of the yoke.
U.S. Pat. No. 2,428,651 issued to Buese on Oct. 7, 1947 discloses a kingpin assembly having a threaded end which engages a threaded aperture through the lower arm of the spindle. The upper end of the kingpin assembly has a shoulder section that extends through a hole in the upper arm of the spindle. The kingpin extends through the knuckle support of the axle and is manually threaded through the threaded aperture until the shoulder section abuts the upper bearings and forces then are forced downwardly which in turn forces the knuckle support downwardly against the lower bearings thereby eliminating any longitudinal movement of the axle with respect to the spindle. This kingpin assembly requires the use of a kingpin with an integral threaded end, an integral shoulder section, and an integral wrench engaging head.